While the update is ready for Nokia Phones (we haven’t heard about others, as of yet, but the experience should be similar), you’re still going to have to wait for your mobile operator to release the update. From the Nokia Conversations post:

The Windows Phone 7.8 update is now rolling out for Nokia Lumia smartphones through February. Delivery of the update is operator dependent, meaning you will receive a notification in the coming weeks if you have an unlocked phone or if your operator has approved the update. If you don’t receive the update notification within the next three weeks, please contact your operator for more information.

Do you have a Windows Phone 7.8 device? Have you received an update notice? Let us know when you do, either in the comments here or on Twitter @liveside.